Many computer users today interact with more than one machine. For example, a single user might operate a desktop machine at work, a laptop machine when traveling, and a cellular telephone machine at home. While the applications themselves (e.g., email, browser, and word processing) may be shared across the machines, in many cases the data resulting from activities conducted on the machines when executing the applications is not.
For example, the user might be running a browser at home on his laptop to scan the Internet for articles relating to a work project, recording several bookmarks during the time the laptop is in use. Later, using the desktop computer at the office, the bookmarks may be lost, so that manual re-entry is required to add them into the browser application used at work. Similarly, the browsing history, logged at the laptop, may also be lost, and perhaps, impractical or impossible to recreate on the desktop. Additional difficulties may exist with respect to synchronizing instant message history, as well as other applications, across multiple machines.